Effect of Spinning and Milling Time on Thermoelectric Properties of the p-type (Bi0.25Sb0.75)2Te3 Alloy

A series of p type bulk (Bi0.25Sb0.75)2Te3 thermoelectric materials were prepared by melt spinning-mechanical milling (MM) and spark plasma sintering (SPS). Electrical conductivity, Seebeck coefficient and thermal conductivity of the sintered samples were measured in the temperature range from 300K to 523K. The effects of milling time on thermoelectric properties were investigated in system. The results show that, with the extension of milling time, the electrical conductivity of the sample increases and then decreases, Seebeck coefficient changes little, while the thermal conductivity decreases with the increase of milling time. As a result, the bulk milled for 20h has the highest ZT value 0.96 at room temperature, meanwhile the bending strength reaches 91MPa.